STEERING COLUMN FOR A MOTOR VEHICLE

Abstract

A steering column that is adjustable by a motor may include a supporting unit that is attachable to a vehicle body, an actuating unit held by the supporting unit, a steering spindle mounted in the actuating unit rotatably about a longitudinal axis, an adjusting drive for adjusting the actuating unit relative to the supporting unit via a threaded spindle and spindle nut, and a drive unit by which the threaded spindle can be driven rotationally relative to the spindle nut. To improve compactness and greater structural freedom, the drive unit may be connected via a flexible drive connection to a gear unit that can be moved spatially relative to the drive unit.

Claims

1.-10. (canceled)

11. A steering column for a motor vehicle, which steering column is adjustable via a motor, wherein the steering column comprises: a supporting unit that is attachable to a body of the motor vehicle; an actuating unit held by the supporting unit; a steering spindle mounted in the actuating unit such that the steering spindle is rotatable about a longitudinal axis; an adjusting drive that is connected to the supporting unit and to the actuating unit, wherein the adjusting drive is configured to adjust the actuating unit relative to the supporting unit, wherein the adjusting drive includes a threaded spindle that engages in a spindle nut; and a drive unit configured to drive the threaded spindle rotationally relative to the spindle nut, wherein the drive unit is connected via a flexible drive connection to a gear unit that is movable spatially relative to the drive unit.

12. The steering column of claim 11 wherein the flexible drive connection includes a flexible shaft.

13. The steering column of claim 11 wherein the gear unit comprises a gearwheel that is connected fixedly to and rotates with the spindle nut or the threaded spindle, wherein the gearwheel is rotatably drivable by the drive connection.

14. The steering column of claim 11 wherein the drive unit comprises a drive motor to which the drive connection is connected on an output side.

15. The steering column of claim 11 wherein the actuating unit includes a casing unit in which a casing tube is mounted, with the steering spindle being mounted within the casing tube, wherein the casing tube is adjustable telescopically in a direction of the longitudinal axis.

16. The steering column of claim 11 comprising an energy absorption device disposed between the gear unit and the supporting unit.

17. The steering column of claim 16 wherein the energy absorption device includes a first energy absorption element that is plastically deformable upon movement of the gear unit in a direction of an axis of the threaded spindle relative to the supporting unit.

18. The steering column of claim 17 wherein the gear unit includes a deformation member by which a second energy absorption element is plastically deformable upon movement of the gear unit relative to the supporting unit.

19. The steering column of claim 17 wherein the energy absorption device includes a switching device for coupling or decoupling the second energy absorption element between the gear unit and the supporting unit.

20. The steering column of claim 11 comprising a rupture element disposed between the gear unit and the supporting unit.

Description

DESCRIPTION OF THE DRAWINGS

[0050] Advantageous embodiments of the invention will be explained in greater detail in the following text on the basis of the drawings, in which, in detail:

[0051] FIG. 1 shows a steering column according to the invention in a diagrammatic perspective view,

[0052] FIG. 2 shows the steering column according to FIG. 1 in a diagrammatic perspective view from the opposite side,

[0053] FIG. 3 shows the steering column according to FIG. 1 in a diagrammatic perspective view from below,

[0054] FIG. 4 shows a detailed view of the gear unit of the steering column according to FIG. 1 in an open state,

[0055] FIG. 5 shows the steering column according to FIG. 1 in a diagrammatic perspective view in a partially exploded state,

[0056] FIG. 6 shows the steering column according to FIG. 1 in a plan view in the normal operating state,

[0057] FIG. 7 shows the steering column according to FIG. 6 in a plan view in the state after the case of a crash (crash state),

[0058] FIG. 8 shows an enlarged detail view as in FIG. 6 of the energy absorption dew vice in a second embodiment in the normal operating state,

[0059] FIG. 9 shows an enlarged detailed view as in FIG. 6 of the energy absorption device in a third embodiment in the normal operating state,

[0060] FIG. 10 shows a view of the energy absorption device according to FIG. 9 after the case of a crash (crash state),

[0061] FIG. 11 shows an enlarged detailed view as in FIG. 6 of the energy absorption device in a fourth embodiment in the normal operating state,

[0062] FIG. 12 shows a diagrammatic longitudinal section through an energy absorption device in an alternative embodiment.

EMBODIMENTS OF THE INVENTION

[0063] In the various figures, identical parts are always provided with the same designations, and are therefore as a rule also named or mentioned in each case only once.

[0064] FIGS. 1, 2 and 3 show a steering column 1 according to the invention in diagrammatic perspective views obliquely from the top left (FIG. 1) and obliquely from the right (FIG. 2) and from below (FIG. 3) toward the rear end, as viewed in the driving direction of a vehicle (not shown).

[0065] The steering column 1 comprises a supporting unit 2 which can be attached via fastening bores 21 to a vehicle body (not shown). An actuating unit 3 is held by the supporting unit 2, in which actuating unit 3 a steering spindle 31 is mounted such that it can be rotated about a longitudinal axis L. The actuating unit 3 is supported on the supporting unit 2 in the direction of the longitudinal axis L. At the rear end with regard to the driving direction, the steering spindle 31 is provided with a fastening section 32 for attaching a steering wheel (not shown here).

[0066] The actuating unit 3 has a casing unit 33 which is mounted such that it can be pivoted relative to the supporting unit 2, with the result that the fastening section 32 can be adjusted in a vertical direction H for vertical adjustment.

[0067] A casing tube 34 (also called an inner casing tube or an internal casing tube) can be adjusted in the casing unit 33 in an axially telescopic manner in the longitudinal direction, that is to say the direction of the longitudinal axis L, in order to realize a longitudinal adjustment, as indicated by way of the double arrow.

[0068] For the longitudinal adjustment, an adjusting drive 4 according to the invention is provided which comprises a drive unit 41 and a gear unit 42 which are separated from one another spatially and are connected to one another via a flexible drive connection in the form of a flexible shaft 43.

[0069] The drive unit 41 comprises an electric motor 411 which is flange-connected on the input side to a step-down gear mechanism 412. On the output side, the rotatable shaft core of the flexible shaft 43 is coupled to the step-down gear mechanism 412. The drive unit 41 is fastened to the casing unit 33, and is connected fixedly to the supporting unit 2 in this way at least in the direction of the longitudinal axis L.

[0070] The gear unit 42 has a gear housing 421 which is partially omitted in the view of FIG. 4, in order to provide a view of the interior.

[0071] The adjusting drive 4 is configured as what is known as a plunger spindle drive, with a threaded spindle 44 which extends with its spindle axis S parallel to the longitudinal axis L, and which is connected to the casing tube 34 in a manner which is secured against relative rotation with respect to the longitudinal axis L.

[0072] The threaded spindle 44 is screwed into a spindle nut 45 which is connected coaxially to a gearwheel 46 which is mounted in the gear unit 42 so that it can be rotated about the spindle axis S. The spindle thread which is not shown in detail can also be configured in the gearwheel 46, as a result of which the spindle nut 45 is therefore of integrated configuration.

[0073] An intermediate gear 47 has a toothing system which corresponds with the gearwheel 46, and is mounted in the gear unit 42, with the result that it meshes with the gearwheel 46. The intermediate gear 47 is coupled in a torque-transmitting manner to the flexible shaft 43.

[0074] An energy absorption device 5 is arranged between the gear unit 42 and the casing unit 33, the functional elements of which energy absorption device 5 can be seen in the illustration of FIG. 5, in which the spindle drive including the gear unit 42 and the threaded spindle 44 is shown diagrammatically in a manner which is exploded transversely with respect to the longitudinal axis L.

[0075] The energy absorption apparatus 5 comprises an elongate, U-shaped guide profile 51 which is fixed by means of screws laterally to the supporting unit 2 parallel to the longitudinal axis L. As can be seen in FIGS. 1, 3 and 4, the gear unit 42 is held between the U-limbs of the guide profile 51.

[0076] For the actual energy absorption, the guide profile 51 has crash slots 52 which are elongate in the direction of the longitudinal axis L. In each case one deformation member in the form of a mandrel 53 dips into each of the crash slots 52, as can be seen clearly in the detailed view of FIGS. 6 and 8.

[0077] Each mandrel 53 has a cross section with a width which is greater than the slot width of the corresponding crash slot 52.

[0078] In the normal operating state, that is to say before a crash case has occurred, the mandrel 53 is situated at the rear end of the crash slot 52, as shown in FIG. 6.

[0079] A rupture element in the form of a shear bolt 54 can be arranged between the gear unit 42 and the casing unit 33, which shear bolt 54 is fixed in a positively locking manner through a fastening opening 422 in the gear housing 421 in a corresponding opening 512 in the guide profile 51.

[0080] If a great crash force F acts forward in the direction of the longitudinal axis on the steering spindle 31 in the case of a crash, as shown in FIG. 6, said crash force is transmitted via the casing tube 34 and the threaded spindle 44 which is supported on it, the spindle nut 45 and the gearwheel 46 to the gear unit 42. If the crash force F exceeds a predefined limit value, the shear bolt 54 ruptures. The gear unit 42 is then moved along the guide profile 51 by way of the crash force F, as indicated in FIG. 7 by way of the arrow on the gear unit 42. Here, the casing tube 34, the steering spindle 31, the threaded spindle 44 and the gear unit 42 move relative to the guide profile 51, the casing unit 33 and the drive unit 41 with the absorption of energy.

[0081] By way of the relative movement in the case of a crash, the mandrel 53 is moved along in the crash slot 52, as a result of which said crash slot 52 is plastically widened progressively with the absorption of kinetic energy. The section 52a which is widened in the process can be seen in FIG. 7.

[0082] As can be seen from FIGS. 6 and 7, the drive unit 41 remains in its position relative to the casing unit 33 and to the supporting unit 2. The relative movement in the case of a crash brings about a deformation and therefore yielding of the flexible shaft 43, as a result of which the relative movement of the gear unit 42 for energy absorption is practically not impaired. In the case of a crash, therefore, the gear unit 42 can be displaced relative to the drive unit 41.

[0083] FIG. 8 shows a second embodiment, in the case of which the crash slot 52 tapers in a wedge-shaped manner toward its front end 52b (to the right in the drawing). As a result, in the case of a crash, the deformation work which is required for widening increases along the crash travel of the gear unit 42 relative to the casing unit 33, with the result that a progressive energy absorption characteristic is realized. Here, the crash slot 52 has side walls, said side walls preferably converging in a wedge-shaped manner at an angle of less than or equal to 10°.

[0084] FIGS. 9 and 10 show a third embodiment which has two crash slots 52 which run adjacently in a limb of the U-profile 51. While the outer outside edges of the two slots 52 run in parallel, the inner edges delimit a web 55 which tapers in a wedge-shaped manner toward the rear and, after the case of a crash, is deformed plastically in the widened section 52a, as shown in FIG. 10. Here, two mandrels 53 are provided, said mandrels being spaced apart from one another and the web 55 being arranged between them. In the case of a crash, the mandrels 53 are displaced relative to the web 55 of the guide profile 51, said web 55 being moved through the mandrels 53 and being deformed plastically in the process. This can be gathered particularly clearly from FIG. 10, in the case of which a section of the web 55 is deformed.

[0085] The fourth embodiment which is shown in FIG. 11 differs from the embodiment which is shown in FIG. 8 in that there is an additional, second mandrel 56 which has a smaller cross section than the first mandrel 53. By virtue of the fact that the first mandrel 53 can optionally be removed from the crash slot 52 by means of a pyrotechnical actuator (not shown), only the second mandrel 56 is then active. As a result of its smaller cross section, a smaller amount of deformation work has to be applied for the passage through the crash slot 52. In this way, a lower crash level can be set by way of deactivation of the first mandrel 53. In this way, two different crash levels can be produced in a simple way.

[0086] FIG. 12 diagrammatically shows a longitudinal section through the energy absorption device 5. It is apparent from this that an additional or alternative energy absorption element can be arranged in the form of a bending strip 57 between the gear unit 42 and the casing unit 33. The bending strip 57 is hooked by way of an inlet-side limb 571 in the direction of the spindle axis S behind a driver 423 which is configured on the gear unit 42. The other, outlet-side limb 572 is connected via a substantially U-shaped bend 573 to the first limb 571, and is supported in the direction of the longitudinal axis L against an abutment 513 on the guide profile 51 or the casing unit 33.

[0087] If, in the case of a crash, the gear unit 42 is displaced relative to the casing unit 33 in the forward direction in the direction of the longitudinal axis L (to the right in the drawing), a continuous plastic deformation of the limb 572 takes place in the bend 573 which is then run through. As a result, crash energy is likewise absorbed continuously. The dimensions of the limb 572 can vary over the longitudinal extent of the limb 572.

[0088] As an alternative or in combination, the energy absorption device 5 can have different arrangements of bending strips 57, mandrels 53, 56 which engage into crash slots 52, and other energy absorption devices which make an absorption of kinetic energy possible by way of conversion into deformation and friction.

[0089] For vertical adjustment, a second adjusting drive 7 can be provided which can be seen in FIG. 2, and is configured as a conventional rotating spindle drive in the example which is shown. Here, the spindle nut 71 which can be displaced in a translational manner and into which a rotationally drivable threaded spindle 72 engages is articulated on an adjusting lever 73 which is inserted between the casing unit 33 and the supporting unit 2 such that it can be pivoted in the vertical direction H. In a deviation from the drawing, the adjusting drive 7 can in principle also be configured like the first adjusting drive 4 according to the invention.

LIST OF DESIGNATIONS

[0090] 1 Steering column [0091] 2 Supporting unit [0092] 21 Fastening bores [0093] 3 Actuating unit [0094] 31 Steering spindle [0095] 32 Fastening section [0096] 33 Casing unit [0097] 34 Casing tube [0098] 4 Adjusting drive [0099] 41 Drive unit [0100] 411 Motor [0101] 412 Step-down gear mechanism [0102] 42 Gear unit [0103] 421 Gear housing [0104] 422 Fastening opening [0105] 423 Driver [0106] 43 Flexible shaft [0107] 44, 72 Threaded spindle [0108] 45, 71 Spindle nut [0109] 46 Gearwheel [0110] 47 Intermediate gear [0111] 5 Energy absorption device [0112] 51 Guide profile [0113] 512 Opening [0114] 513 Abutment [0115] 52 Crash slot [0116] 52a Widened section [0117] 52b Front end [0118] 53, 56 Mandrel [0119] 54 Shear bolt [0120] 55 Web [0121] 57 Bending strip [0122] 571 Limb [0123] 572 Limb [0124] 573 Bend [0125] 7 Adjusting drive [0126] 73 Adjusting lever [0127] L Longitudinal axis [0128] H Vertical direction [0129] S Spindle axis [0130] F Crash force